Microsoft Office 365 is a subscription service that provides you with the latest version of the Office desktop applications that you’re already familiar with, such as Word, Excel, and PowerPoint.
Even though Office 365 is a cloud-based service, Office applications don’t run in the cloud. Instead, users download Office applications from the Office 365 portal and install them on their local computers. Microsoft uses Click-to-Run technology to make the download and installation of Office applications fast and simple. Click-to-Run uses virtualization technology to run Office applications in a self-contained environment on a local computer, which allows users to run Office applications side-by-side with earlier versions of Office.
Office applications are available in 32-bit and 64-bit editions.